1. Field of the Invention
This invention relates to a process of purification of non-biodegradable industrial wastewaters.
2. Description of the Prior Art
One of the most economical and commonly employed methods of wastewater treatment involves the use of microorganisms to consume the contaminants in the wastewater. However, there are many industrial processes which produce wastes of such obnoxious and toxic character that organisms cannot exist therein and biological treatment therefore becomes impractical. Furthermore, the increasing cost of fuel and the enforcement of stricter air pollution standards have made incineration of such wastes uneconomical or impractical. Since viable surface treatment alternatives do not exist these effluents are frequently dumped at sea or are disposed of by injection into deep wells.
The wet oxidation process (oxidation in the presence of water at elevated temperature and pressure) has been known for about a quarter of a century as a useful method of disposal of a wide variety of waste substances and in purification of wastewaters containing pollutants; cf. Zimmermann U.S. Pat. Nos. 2,665,249, 2,824,058 and 2,903,425.
The term "wet oxidation" is intended to apply to any oxidation effected in an aqueous medium at elevated temperature and pressure with any gas containing oxygen. While ordinary air is the most readily available source of an oxygen containing gas, any other gas mixture containing oxygen as well as pure oxygen may be used.
Pradt U.S. Pat. No. 3,876,536 describes a process for treating sewage sludge or night soil by wet oxidation followed by biological oxidation by aeration in the presence of biomass and powdered activated carbon and regeneration of the carbon by wet oxidation. There is no disclosure of application of the process to non-biodegradable industrial wastes.